I'm not convinced removing momentum favours hammers over axes. On the one-hand 10str from a 5lb is better for the hammer then the axe. On the other it's slightly easier to find heavy hammers than heavy axes. I don't know the weight range is pretty close.

fwiw, I like that analysis. In a game without Momentum, it would probably be a good idea to tweak hammer weights a bit. Maybe a median weight around 7 lbs.--i.e. greatsword weight--is a good idea. It might also be a good idea to give dwarves a racial bonus with warhammers in addition to axes.